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What is endurance training?

Kjekt å vite

Endurance is the ability of the muscles to perform work over some time. When you exercise endurance, your muscles burn energy, preferably in the form of carbohydrates and fats, with the help of oxygen. The oxygen supply to your muscles is, therefore, an essential factor that affects your endurance. Endurance training is also crucial for the heart's ability to pump blood around the body.

If your muscles get too little oxygen, it will lead to an accumulation of lactic acid, which causes the muscles to stiffen, and you will have to stop working —also called anaerobic endurance. If, on the other hand, your muscles do get enough oxygen, it is called aerobic endurance. Then you will keep lactic acid at a distance, and be able to perform a much longer work.

Test your oxygen uptake with Myworkout GO. Download it for free for iOS or Android.

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Endurance training run

Endurance training increases the heart's pumping capacity.
But what determines if you can get enough oxygen to your muscles?

The heart!

Professor of medicine, Jan Hoff, says the whole purpose of endurance training is to increase the size and elasticity of the heart and blood vessels, which in turn increases the maximum oxygen uptake.

  • In average 20-year-old men, the heart's pumping capacity is about 20 litres per minute. In a top endurance athlete, on the other hand, the capacity is double, which is equivalent to four kitchen taps more blood at full opening, says Hoff.
  • Our heart, which is only the size of a fist, is a very efficient pump, he adds.

According to the professor, it is only in highly untrained people that the limitation in aerobic endurance is related to conditions in the body's muscles, and not the heart's pumping capacity. If you are in terrible shape, for example, your capillary network, the smallest blood vessels in your body, may be reduced, which will limit the oxygen flow to the muscle cells.

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Endurance training app

Maximum heart rate

Heredity determine your maximum heart rate and it does not change no matter how much you exercise. On the other hand, it decreases slightly with age. The heart's ability to pump blood, therefore depends on how much blood it can pump in each beat - so-called stroke volume.

  • The stroke volume increases as the heart becomes larger with training that challenges the heart volume. With this training the heart becomes more elastic, says Hoff.

In the past, it has been difficult to measure the heart rate. We assumed that you reached full stroke volume if you ran at long-distance intensity, which is about 70 per cent of maximum heart rate. However, research has shown that the stroke volume increases up to an intensity that corresponds to maximum oxygen uptake. A higher intensity than this gives lactic acid, which in turn will lead to a decrease in stroke volume.

Training that works!